feat: initialize React app with TanStack Router and Vitest for testing

- Added App component with basic structure and styling.
- Included CSS for app layout and animations.
- Integrated TanStack Router for routing management.
- Set up Vitest for testing with a basic test case for the App component.
- Added logo SVG for branding.
- Configured Vite for development with React and TanStack Devtools.
- Created reportWebVitals utility for performance measurement.
- Established global styles in styles.css.

my-app/src/reportWebVitals.js

@@ -0,0 +1,13 @@
+const reportWebVitals = (onPerfEntry) => {
+  if (onPerfEntry && onPerfEntry instanceof Function) {
+    import('web-vitals').then(({ onCLS, onINP, onFCP, onLCP, onTTFB }) => {
+      onCLS(onPerfEntry)
+      onINP(onPerfEntry)
+      onFCP(onPerfEntry)
+      onLCP(onPerfEntry)
+      onTTFB(onPerfEntry)
+    })
+  }
+}
+
+export default reportWebVitals